ethdev: support vtune task tracing

ethdev: support vtune task tracing

The patch simplifies DPDK applications analysis for developers which use
Intel® VTune Amplifier.

The empty cycles are such iterations that yielded no RX packets. As far as
DPDK is running in poll mode, wasting cycles is equal to wasting CPU time.
Tracing such iterations can identify that device is underutilized. Tracing
empty cycles becomes even more critical if a system uses a lot of Ethernet
ports.

The patch gives possibility to analyze empty cycles without changing
application code. All needs to be done is just to reconfigure and rebuild
the DPDK itself with CONFIG_RTE_ETHDEV_PROFILE_ITT_WASTED_RX_ITERATIONS
enbled. The important thing here is that this does not affect DPDK code.
The profiling code is not being compiled if user does not specify config
flag.

The patch provides common way to inject RX queues profiling and VTune
specific implementation.

Signed-off-by: Ilia Kurakin <ilia.kurakin@intel.com>
Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>